In Cotard’s syndrome, the feeling of existence corrodes but something more fundamental does not (see “How do I know I exist“). Even though people with this rare condition feel they don’t exist, there is still an “I” experiencing that feeling. What is that “I”? One answer is that it may be a by-product of consciousness itself.

How your brain creates the feeling of being is the biggest problem in neuroscience. But we are coming closer to cracking it

René Descartes was convinced that the body and conscious mind are two different substances: the first is made of matter, the latter is immaterial. His ideas influenced neuroscience until a few decades ago, but the field has moved on. Today, it is widely accepted that our brains give rise to consciousness.

But how? That is a raging debate. At its heart is what philosopher David Chalmers at New York University termed the “hard problem” of consciousness: how can physical networks of neurons produce experiences that appear to fall outside the material world? As Thomas Nagel, also at New York University, put it in the 1970s: you could know every detail of the physical workings of a bat’s brain, but still not know what it is like to be a bat.

“You may know beyond a doubt that you exist, but your ‘I’ could still be an illusion“

Broadly speaking, those trying to solve the hard problem fall into two camps, according to psychologist and philosopher Nicholas Humphrey. There are those who think that consciousness is something real and those who …